Perforation op thermoplastic films

ABSTRACT

A METHOD OF PERFORATING A FILM OF A THERMOPLASTIC MATERIAL COMPRISING PASSING THE FILM UNDER TENSION AROUND AT LEAST PART OF THE SURFACE OF A ROLLER, THE SURFACE HAVING A PLURALITY OF PROJECTIONS THEREON WHICH ARE ARRANGED IN THE PATTERN CORRESPONDING TO THAT WHICH IS REQUIRED FOR THE PERFORATIONS IN THE FILM AND WHICH ARE MAINTAINED AT A TEMPERATURE SUFFICIENT TO MELT THE FILM, WHEREIN THE FILM IS HELD AGAINST THE ROLLER SOLELY BY VIRTUE OF THE TENSION IN THE FILM. APPARATUS FOR CARRYING OUT THIS METHOD IS ALSO DISCLOSED. THE METHOD AND APPARATUS CAN BE USED FOR PACKAGING PURPOSES.

DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16, 1969, 869 0.6. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets 01! drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent Oflice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED MARCH 5, 1974:

T920,017 PERFORATION 0F THERMOPLASTIC FILMS Peter Ralph Billinghurst, East End Green, near Hertford,

England, assignor to Imperial Chemical Industries Limited, London, England Continuation of abandoned application Ser. No. 137,841, kpnlfll, 1971. This application Sept. 7, 1973, Ser. No.

95, 7 Claims priority, application Great Britain, May 8, 1970, 22,382/70; Feb. 17, 1971, 4,844/71 Int. Cl. B26f 3/10, N24 US. Cl. 83-16 2 Sheets Drawing. 14 Pages Specification A method of perforating a film of a thermoplastic material comprising passing the film under tension around at least part of the surface of a roller, the surface having a plurality of projections thereon which are arranged in the pattern corresponding to that which is required for the perforations in the film and which are maintained at a temperature suflicient to melt the film, wherein the film is held against the roller solely by virtue of the tension in the film. Apparatus for carrying out this method is also disclosed. The method and apparatus can be used for packaging purposes.

March 1974 P. R. BILLINGHURST T920,017

PERFQRATION OF THERMOPLASTIC FILMS Original Filed April 27, 1971 2 Sheets-Sheet l March 5, 1974 P R. BILLINGHURST T920917 PERFQRATION 0F THERMOPLASTIC FILMS Original Filed April 27, 1971 2 Sheets-Sheet 2 m u h v 

